A method of molding a container incorporating surface indicia and the container

ABSTRACT

A method of forming a container ( 1 ) and a container ( 1 ) formed thereby. A preform ( 2 ), having a generally cylindrical body ( 60, 8 ) extending between a closed end ( 12 ) and an open mouth, is placed within a mold ( 20, 22 ) having surfaces corresponding in shape to the desired container ( 1 ). An incompressible medium, which is the end product that remains in the molded container ( 1 ), is injected under pressure into the preform ( 2 ). Under the influence of the incompressible medium, the preform ( 2 ) is expanded into contact with the surfaces defining the cavity, simultaneously forming and filling the container ( 1 ). During expanding of the preform ( 2 ), portions of the plastic material are forced into a series of recesses ( 72 ) defined in the cavity surface ( 82, 85 ). With the incompressible medium contained therein, the container ( 1 ) is removed from the mold ( 20, 22 ) and including a series of raised dots corresponding to the series of recesses ( 72 ) defined in the cavity surface ( 82, 85 ). A method of forming a container ( 1 ) and a container ( 1 ) formed thereby. A preform ( 2 ), having a generally cylindrical body ( 60, 8 ) extending between a closed end ( 12 ) and an open mouth, is placed within a mold ( 20, 22 ) having a surfaces corresponding in shape to the desired container ( 1 ). An incompressible medium, which is the end product that remains in the molded container ( 1 ), is injected under pressure into the preform ( 2 ). Under the influence of the incompressible medium, the preform ( 2 ) is expanded into contact with the surfaces defining the cavity, simultaneously forming and filling the container ( 1 ). During expanding of the preform ( 2 ), portions of the plastic material are forced into a series of recesses ( 72 ) defined in the cavity surface ( 82, 85 ). With the incompressible medium contained therein, the container ( 1 ) is removed from the mold ( 20, 22 ) and including a series of raised dots corresponding to the series of recesses ( 72 ) defined in the cavity surface ( 82, 85 ).

BACKGROUND 1. Technical Field of the Invention

The present invention relates to molded containers, and moreparticularly to molded containers having tactile writing or otherindicia molded into various portions of the container.

2. Related Technology

Plastic containers for liquids are manufactured by various differentmethods. In most methods, a plastic preform is heated to a suitabletemperature for molding, placed within a mold and then expanded axiallyand radially to form the container. In certain processes, air is used asa blow molding medium to expand the preform.

The shoulders, sidewalls and base portions of such containers are oftenmolded so as to present a design/indicia) that may be visually perceivedby the end user. In some instances, the design/indicia is an aestheticpleasing pattern to provide distinctiveness to the container. In otherinstances, the design/indicia may be a logo or trademark.

While the level of detail in the designs that can be molded into suchcontainer is acceptable for presenting large distinctive patterns andlarge logos, the level of detail is unacceptable for presenting smallerpatterns and logos, and in particular for presenting smaller readablelettering or tactile writing, such a braille, as may be wanted toidentify the contents of the container or provide other information tothe end user. Currently, such information is provided in print orembossed form on the label of the container, but not the containeritself

In the field known as hydraulic blow molding, or sometimes liquid blowmolding or hydroforming, it is known to inject a liquid under pressureinside a preform already placed in a mold to shape a container accordingto the cavity shape of the mold and fill the shaped container with theliquid at the same time. Advantageously, the injected liquid is the endproduct retained in the container, i.e. the product which is intended tobe provided to a consumer using the container.

Hydraulic blow molding has several advantages compared to theconventional air blowing techniques. In the latter technique, thepreform is formed into the container by first injecting a compressedgas, for example pressurized air, into the preform. The formed containeris subsequently filled with the end product, either directly afterwardby an adjacent filling machine and station or later after transportingthe empty container to a filling facility. Obviously, one of theadvantages of hydraulic blow molding is that the obtained container issimultaneously filled with the end product.

In hydraulic blow molding, the filled containers can be produced at ahigher rate since the forming step of the container is not separatedfrom the filling step. The energy cost of hydraulic blow molding isreduced since there is no need to produce the compressed gas used in airblow molding with air. Additionally, higher pressures can be imparted tothe preform with an incompressible liquid instead of air, which iscompressible. Such pressures allow one to obtain a container having avery satisfactory shape since the wall of the preform is urged againstthe wall of the mold in an optimal manner. U.S. Pat. No. 8,573,964discloses a hydraulic blow molding technique, which is hereinincorporated by reference in its entirety.

SUMMARY

In one aspect of the invention, a method of forming a container ofplastic material is provided, the method comprising the steps of:providing a preform of the plastic material, the preform including anopen end defined by a mouth, a closed end and a generally cylindricalbody extending between the closed end and the mouth; placing the preformwithin a mold having surfaces defining a cavity corresponding in shapeto the container; injecting an incompressible medium under pressure intothe preform, the incompressible medium being an end product remaining inthe molded container; expanding the preform in the cavity under theinfluence of the incompressible medium into contact with the surfacesdefining the cavity and simultaneously forming and filling thecontainer; during expanding of the preform, forcing portions of theplastic material into a series of recesses defined in the cavitysurface, each of the recesses having a common depth; and removing thecontainer with the incompressible medium contained therein from themold, the container including a series of raised dots corresponding tothe series of recesses defined in the cavity surface.

In another aspect, the recesses are provided in a portion of the cavitydefining one of a shoulder or base of the container.

In a further aspect, the recesses are provided adjacent to a portiondefining a sidewall of the container.

In additional aspect, the recesses and the raised dots define a depth toheight ratio of less than 9:1.

In another aspect, the recesses and the raised dots define a depth toheight ratio of less than 3:1.

In a further aspect, the recesses and the raised dots define a relieffactor of greater than 0.11.

In an additional aspect, the recesses and the raised dots define arelief factor of greater than 0.3.

In another aspect, the incompressible medium is injected at a pressureof less than 40 bar.

In a further aspect, the incompressible medium is injected at a pressureof less than 36 bar.

In an additional aspect, the incompressible medium is injected at apressure in the range of 30 to 35 bar.

In another aspect, the incompressible medium is injected with a peakpressure of less than 40 bar.

In a further aspect, the incompressible medium is injected with a peakpressure of less than 36 bar.

In an additional aspect, the incompressible medium is injected with apeak pressure in the range of 30 to 35 bar.

In another aspect, each of the raised dots extends from an immediatelysurrounding surface of the molded container to a nominal height of notless than 0.2 mm, more preferably greater than 0.25 mm and mostpreferably greater than 0.258 mm.

In a further aspect, the series of raised dots define a tactile writingfeature.

In an additional aspect, the series of raised dots define a tactilewriting feature comprised of a plurality of equidistantly spaced cellsand each cell including a character formed by not more than six of theraised dots.

In another aspect, each of the raised dots has a nominal base diameterin the range of greater than 1.4 mm to less than 1.7 mm

In a further aspect, the invention provides a molded container ofplastic material, the molded container comprising: a neck defining anopening into the molded container; a body extending from the finish andincluding a shoulder adjacent the finish, a base defining a closed endof the container, and a sidewall extending between the shoulder and thebase; and a series of raised dots defining tactile writing featureformed on a surface of the container and being defined by the plasticmaterial forming the container.

In an additional aspect, the tactile writing feature is formed on atleast one of the shoulder and the base.

In another aspect, the tactile writing feature is formed adjacent to thesidewall on at least one of the shoulder and the base.

In a further aspect, each of the raised dots extends from an immediatelysurrounding surface of the molded container to a nominal height of notless than 0.2 mm, more preferably greater than 0.25 mm and mostpreferably greater than 0.258 mm.

In an additional aspect, each of the raised dots extends from animmediately surrounding surface of the molded container to a nominalheight of between 0.25 mm and 0.6 mm.

In another aspect, the raised dots has a nominal base diameter of notmore than 1.69 mm.

In a further aspect, each of the raised dots has a nominal base diameterin the range of 1.4 mm to less than 1.7 mm and extends from animmediately surrounding surface of the molded container to a nominalheight in the range of 0.25 mm to less than 0.9 mm.

In an additional aspect, the tactile writing feature is comprised of aplurality of equidistantly spaced cells and each cell including acharacter formed by not more than six of the raised dots.

In another aspect, a method of forming a molded container of plasticmaterial is provided, the method comprising the steps of: providing apreform of the plastic material; placing the preform within a moldhaving cavity surfaces defining a cavity corresponding in shape to adesired shape of the container; injecting an incompressible medium underpressure into the preform, the incompressible medium being an endproduct remaining in the molded container; expanding the preform in thecavity under the influence of the incompressible medium into contactwith the cavity surfaces and simultaneously forming and filling themolded container with a shape extending from a neck defining an openinginto the molded to a base defining a closed end of the molded container;during expanding of the preform, forcing portions of the plasticmaterial into recesses in the cavity surfaces that form part of aembossed texture on a surface of the container; and removing thecontainer from the mold wherein the resulting embossed texture on thecontainer has a roughness average S_(a) that is at least 40% greaterthan the roughness average S_(a) of the corresponding embossed textureof a container molded in the same mold using pressurized air.

In a further aspect, a molded container of plastic material is provided,the container comprising: a neck defining an opening into the moldedcontainer, a body extending from the neck and including a base defininga closed end of the molded container; embossed texture being formed on asurface of the plastic container and being defined by the plasticmaterial forming the molded container, wherein the embossed texture hasa roughness average S_(a) that is at least 40% greater than theroughness average S_(a) of the corresponding embossed texture of acontainer molded in the same mold using pressurized air.

In an additional aspect, the invention provides a molded container ofplastic material is provided having a neck defining an opening into themolded container, a body extending from the neck and including a basedefining a closed end of the molded container; a tactile writing beingformed on a surface of the plastic container and being defined by theplastic material forming the molded container, the tactile writing beingcomprised of a plurality of equidistantly spaced cells; and each cellincluding a character formed by not more than six raised dots, whereineach of the raised dots has a nominal base diameter of not more than0.063 inches and extends from an immediately surrounding surface of themolded container to a nominal height of not more than 0.037 inches.

In another aspect, each of the raised dots has a nominal base diameterof not more than 0.057 inches and extends from an immediatelysurrounding surface of the molded container to a nominal height of notmore than 0.019 inches.

In another aspect of the invention, a method of forming a moldedcontainer of plastic material is provided and includes the steps of:providing a preform of the plastic material; placing the preform withina mold having cavity surfaces defining a cavity corresponding in shapeto a desired shape of the container; injecting an incompressible mediumunder pressure into the preform, the incompressible medium being an endproduct remaining in the molded container; expanding the preform in thecavity under the influence of the incompressible medium into contactwith the cavity surfaces and simultaneously forming and filling themolded container with a shape extending from a neck defining an openinginto the molded to a base defining a closed end of the molded container;during expanding of the preform, forcing portions of the plasticmaterial into recesses in the cavity surfaces and forming part of atactile writing impression, the tactile writing impression beingcomprised of a plurality of equidistantly spaced cells, and each celldefining a character formed by six or less of the recesses, wherein eachof the recesses has a nominal base diameter of not more 10% greater than0.063 inches and is recessed from an immediately surrounding surface ofthe cavity surface to a nominal depth of not more than 10% greater than0.037 inches; and removing the molded container with the incompressiblemedium contained therein from the mold.

In a further aspect, the method includes expanding of the preform, theplastic material is forced into the recesses and each of the recesseshas a nominal base diameter of not more than 10% greater than 0.057inches and is recessed from an immediately surrounding surface of thecavity surface to a nominal depth of not more than 10% greater than0.019 inches.

In another aspect of the invention, a molded container of plasticmaterial is provided having a neck defining an opening into the moldedcontainer, a body extending from the neck and including a base defininga closed end of the molded container; embossed features (design/indicia)being formed on a surface of the plastic container and being defined bythe plastic material forming the molded container, wherein the embossedfeatures have a mean surface height profile not less than 80% andpreferably not less than 85% of the depth of the correspondingdepression feature defining the embossed feature and provided in themold forming the container.

In another aspect of the invention, a method of forming a moldedcontainer of plastic material is provided and includes the steps of:providing a preform of the plastic material; placing the preform withina mold having cavity surfaces defining a cavity corresponding in shapeto a desired shape of the container; injecting an incompressible mediumunder pressure into the preform, the incompressible medium being an endproduct remaining in the molded container; expanding the preform in thecavity under the influence of the incompressible medium into contactwith the cavity surfaces and simultaneously forming and filling themolded container with a shape extending from a neck defining an openinginto the molded to a base defining a closed end of the molded container;during expanding of the preform, forcing portions of the plasticmaterial into recesses in the cavity surfaces and forming part of aembossed feature (design/indicia), the embossed feature

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects and advantages of the invention will appear upon readingthe following description, given by way of example and made in referenceto the appended drawings, wherein:

FIG. 1 is a schematic illustration of a machine for producing containersfrom preforms in accordance with the principles of the presentinvention;

FIG. 2 is a diagrammatical cross-section views of part of a formingstation at an initial stage of forming of a container;

FIGS. 3 and 4 are diagrammatical cross-section views of part of aforming station at subsequent stages of form a container;

FIGS. 5 and 6 are side views of containers formed in accordance with theprinciples of the present invention;

FIG. 7 is an enlarged, cross-sectional view of a braille dot on acontainer wall and a corresponding recess in the mold;

FIGS. 8A, 8B and 8C are front, left side and right side view of acontainer formed in accordance with the principles of the presentinvention, having various indicia formed therein and showing locations1-6 analyzed herein;

FIGS. 9A and 9B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 1 on an air blown container;

FIGS. 10A and 10B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 1 on a liquid blown container;

FIGS. 11A and 11B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 2 on an air blown container;

FIGS. 12A and 12B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 2 on a liquid blown container;

FIGS. 13A and 13B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 3 on an air blown container;

FIGS. 14A and 14B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 2 on a liquid blown container;

FIGS. 15A and 15B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 4 on an air blown container;

FIGS. 16A and 16B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 4 on a liquid blown container;

FIGS. 17A and 17B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 5 on an air blown container;

FIGS. 18A and 18B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 5 on a liquid blown container;

FIGS. 19A and 19B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 6 on an air blown container;

FIGS. 20A and 20B are respectively two dimensional (2D) and threedimensional (3D) images taken at location 6 on a liquid blown container;

FIG. 21A is the two dimensional (2D) image of the air blown container atlocation 4 and shows the locations of x and y profiles for sectionalanalysis;

FIG. 21B shows the sectional analysis of the x and y profiles of the airblown container at location 4;

FIG. 22A is the two dimensional (2D) image of the liquid blown containerat location 4 and shows the locations of x and y profiles for sectionalanalysis;

FIG. 22B shows the sectional analysis of the x and y profiles of theliquid blown container at location 4;

FIG. 23A is the two dimensional (2D) image of the air blown container atlocation 5 and shows the locations of x and y profiles for sectionalanalysis;

FIG. 23B shows the sectional analysis of the x and y profiles of the airblown container at location 5;

FIG. 24A is the two dimensional (2D) image of the liquid blown containerat location 5 and shows the locations of x and y profiles for sectionalanalysis;

FIG. 24B shows the sectional analysis of the x and y profiles of theliquid blown container at location 5;

FIG. 25A is the two dimensional (2D) image of the air blown container atlocation 6 and shows the locations of x and y profiles for sectionalanalysis;

FIG. 25B shows the sectional analysis of the x and y profiles of the airblown container at location 6;

FIG. 26A is the two dimensional (2D) image of the liquid blown containerat location 6 and shows the locations of x and y profiles for sectionalanalysis; and

FIG. 26B shows the sectional analysis of the x and y profiles of theliquid blown container at location 6.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, the terms “upper” and “lower” are definedrelative to an axis, axis A, which corresponds to the axis of thepreform and the container to be produced and which extends generallyvertically when the container is placed on its base. The terms“upstream” and “downstream” are defined relative to the direction inwhich the preforms and the containers circulate in the machine shown inFIG. 1. The term “liquid” has a physical meaning and encompasses anyflowable, incompressible medium.

Referring now to FIG. 1, an apparatus or machine for forming and fillinga container 1 from a preform 2 is generally illustrated therein. In themachine, a forming and filling station 4, receives the preforms 2 andoutputs a formed and filled containers 1. For simplicity and brevity,the term “forming and filling station 4” is hereafter simply referred toas “forming station 4.”

The machine is arranged so that it receives successive preforms 2, eachmade of a thermoplastic material. The thermoplastic material is forexample chosen among the polyesters, such as polyethylene terephthalate(PET), polyethylene naphthalene (PEN), polyethylene imine (PEI),polytrimethylene terephthalate (PTT), polylactic acid (PLA),polyethylene furanoate (PEF), or polyolefins, such as polyethylene lowdensity (LDPE) or high density (HDPE), polypropylene (PP), or styrenebased materials such as polystyrene (PS), or other polymers, such aspolyvinyl chloride (PVC) or a mix of these materials.

Each preform 2 has the general shape of a test tube. More specifically,each preform 2 comprises a body 8 having the shape of a tube or cylinderextending along axis A. The preforms 2 are formed at one end with anopen end 10 and at the other end with a closed end 12. The open end 10is may be provided with the final shape of the neck or finish 14 of thecontainer, meaning that the shape of the finish 14 will not be modifiedduring the container forming process. The finish 14 defines an inneropening 16 extending along the longitudinal axis A and is delimited by awall that is outwardly provided with a thread allowing the container 1to receive a correspondingly threaded cap (not shown). Alternatively,the threads may be omitted and the finish 14 closed and sealed by otherknown methods. The closed end 12 has, for example, a hemisphericalshape. The above described shape is given as a non-restricting exampleand other shapes can be foreseen. Additionally, the preform may beprovided in a continuous extruded form, instead of injection molded formas is described above. When provided in an extruded form, the preform isgenerally provided as a continuous tube or cylinder without a thread.

The preforms 2, when provided in the injection molded form, can beproduced at a remote location from the forming machine. In such aninstance, the preforms 2 are formed, stored and shipped from theirlocation of manufacture to the location of the forming machine 4.

In the description that follows, the term “preform” is used to refer tothe preform both in its initial shape, as well as during the formingprocess and its deformation into the container. The term “container” isused to refer to the fully or substantially fully deformed and moldedpreform. Thus, the “container” is the end product that is dischargedfrom the machine.

As seen in FIG. 1, the preforms 2 are successively loaded in the machineand transferred to a heating station 3. The heating station 3 isconventional and will not be described in detail herein. The heatingstation 3 is arranged to heat each of the successive preforms 2 to atemperature between the glass transition temperature and thecrystallization material of the thermoplastic material of the preform 2.As a result, the preforms 2 are brought into a malleable state wherethey are able to be deformed under the influence of an increasedpressure inside of the heated preforms 2. Alternatively, the preforms 2can be injection molded at the same location as the forming machine,such that the injected formed preforms, still warm from the injectionmolding process, are directly transferred to the inlet of the formingmachine. This allows for a reduction in the energy required for heatingthe preforms 2 before the forming step.

Each heated preform 2 is then transferred, by means of a transfer wheel18, to a forming station 4. The transfer wheel 18 includes a placingmechanism arranged to receive a preform and then locate the preform in aforming station 4. The transfer wheel 18 and placing mechanisms areconventional and therefore not further discussed or described herein.

The forming stations 4 are preferably carried by a forming wheel 20rotating around an axis B, which is may be parallel to the axis A. Thenumber of forming stations 4 on the transfer wheel 20 is forillustrative purposes only. The actual number of forming stations 4 onthe forming wheel 20 will depend on the specific design of the formingwheel 20 and machine. The forming and filling step, which aresubsequently described, is carried out in the forming stations 4 duringthe rotation of the forming stations 4 with the forming wheel 20.Rotating in this manner, the forming stations 4 allow for the formingand filling of a plurality of preforms 2 at the same time.

Each forming station 4 includes a mold 22 and an injection head 24. Themold 22 received the preform 2 and the injection head 24 is arranged toinject a forming liquid into the heated preform 2 in the mold 22, asshown in FIGS. 2 to 4. Such a forming station 4 is conventional for ahydraulic blow molding process.

As previously noted, hydraulic blow molding is process that uses apressurized liquid, injected inside of the preform 2 while the preform 2is inside the mold 22, to deform the preform 2 into the container 1 andsimultaneously fill the container 1. The shape of the container 1 isdefined by the internal surfaces forming the mold cavity 26 of the mold22. Advantageously, the injected liquid, or molding medium, is the endproduct contained within the container 1, i.e. the end product that isintended to be provided to a consumer using the container 1.

The hydraulic blow molding technique has several advantages compared tothe conventional air blow molding technique, wherein the container 1 isfirst formed by injecting a compressed gas, for example pressurized air,in the preform 2. One of these advantages is that the obtained container1 is simultaneously filled with the end product. Another advantage isthat the filled containers 1 can be produced at a higher rate since theforming step of the container 1 is not separated from the filling step.The energy cost of hydraulic blow molding is reduced since there is noneed to produce the compressed gas used in air blow molding. Higherpressures can also be easily be imparted to the preform with the formingliquid. Such pressures allow obtaining a container having a verysatisfactory and defined shape since the wall of the preform 2 is urgedagainst the wall of the mold 22 in an optimal manner. US-2014/0174034discloses such a hydraulic blow molding technique.

As noted above, the mold 22 defines the molding cavity 26 in the desiredshape of the container 1 to be produced. The mold 22 includes at leasttwo halves movable relative to each other between an opened position anda closed position. The two halves are, for example, hinged together andare movable in rotation relative to each other around an axissubstantially parallel to the axis A of the preform 2. Each half of themold 22 includes a body defining a hollow recess in the shape of half ofthe container 1 to be formed. According to a non-limiting example, thehollow recess of one half is generally semi-cylindrical and closed atits lower end by a bottom surface having the shape of a semi-circle. Atits upper end, the recess is terminated a tapered shoulder definingportion, and then is semi-cylindrical with a shape substantiallycomplementary to the shape of the body 8 of the preform 2 to hold thepreform 2 in the mold 22. The hollow recess of the other half of themold 22 is symmetrical to the hollow recess described above. In theopened position, the halves of the mold 22 are separated from each othersuch that the preform 2 can be introduced between the two halves. In theclosed position, the two halves are applied against each other to form aclosed mold 22, such that the hollow recesses face each other andtogether define the mold cavity 26 having the shape of the container 1to be formed. The mold 22 may have more than two parts. For example, athird part having the shape of the bottom of the container 1 could beprovided to define the molding cavity 26 with the two halves definingjust the shape of the body of the container 1.

The transfer wheel 18 is arranged to move each preform 2 into a mold 22,which is in the opened position at an inlet position 27 of the formingwheel 20. Once the preform 2 is placed between the open halves of themold 22, the mold 22 is moved into its closed position and carries thepreform 2 in rotation with the forming wheel 20, the mold 22. When thepreform is placed in a mold 22, the molding cavity 26 is hermeticallyclosed by the preform 2. The finish 14 of the preform 2 protrudes fromthe mold 22 such that its inner opening 16 remains accessible fromoutside the mold 22, as shown in FIG. 2.

The injection head 24, which injects the pressurized incompressibleliquid into the preform 2, will now be described. The injection head 24described herein and shown in the figures is an example of an injectiondevice that can be used in hydraulic blow molding methods, and it is tobe understood that other kinds of injection devices can be used with themethods described herein to form the containers 1.

The injection head 24 includes an inlet 28, an outlet 30 and a chamber32 between the inlet 28 and the outlet 30 that places the inlet 28 influid communication with the outlet 30. The inlet 28 is in fluidcommunication with an incompressible forming liquid source 34, forexample a water reservoir, via appropriate conduits and a pressurizationmechanism 36, the latter of which is adapted to transfer the liquid fromthe liquid source 34 to the inlet 28 at a controllable predeterminedpressure. According to the embodiment shown in FIG. 2, thepressurization mechanism 36 is a pump. Alternatively, the pressurizationmechanism 36 can also be formed by a conventional piston or by otherappropriate means allowing controlling the pressure of the liquidinjected in the preform. According to an embodiment, the pressureapplied by pressurization mechanism 36 is variable such that the liquidcan be injected at different pressures in the preform 2.

The forming liquid source 34 is a source of a liquid 35 intended to bethe end product or a component of the end product in the container 1. Asused herein, the term “liquid” is intended to encompass non-gas,flowable mediums. The liquid 35 may therefore have a low viscosity (likewater or alcohol), a medium viscosity (like edible oil or soup) or ahigh viscosity (like catsup or yogurt). Also the liquid 35 may behomogeneous or nonhomogeneous and is not intended to be limited tofoodstuff. Non-limiting illustrative examples of liquids that may beutilized with the present invention include cleansing products (forbody, house or automotive care), medical fluids, industrial fluids,automotive fluids, and agricultural fluids.

The outlet 30 of the injection head 24 is adapted to be placed in liquidtight fluidic communication with the opening 16 formed by the finish 14of the preform 2, and therefore with the inner volume of the preform 2.By liquid tight fluidic communication, it is meant that when the outlet30 is in fluidic communication with the inner volume of the preform 2,the liquid 35 flows only in the inner volume of the preform 2 and notoutside the preform 2.

The outlet 30 is defined by end portions of an injection nozzle 38 andis in fluidic communication with the chamber 32. The injection nozzle 38is movable inside a housing 40 of the injection head 24, in translationalong axis A between a retracted position (seen in FIG. 2) and anextended or active position (seen FIGS. 3 and 4). In the retractedposition, the injection nozzle 38 is sufficiently spaced apart from themold 22 to allow for positioning of a preform 2 in the mold 22 or forretrieval of a formed container 1 from the mold 22. In the extendedposition, the end of the injection nozzle 38 is placed in liquid tightengagement with, preferably, the top sealing surface that defines theend face of the finish 4 of the preform 2.

The chamber 32 of the injection nozzle 38 defines a hollow space having,in one example, a regular cylindrical portion and a conical portionextending between the regular cylindrical portion and the outlet 30 ofthe injection nozzle 38. The diameter of the conical portion is reducedprogressively from the diameter of the regular cylindrical portion tothe diameter of the outlet 30, which is at the end of the conicalportion.

The housing 40 further includes a first upper compartment 42 arranged toreceive actuation device 44 for moving the injection nozzle 38. Theactuation device 44 is, in one example, a pneumatic actuation devicecomprised of a piston, attached to the injection nozzle 38 andhermetically separating the first upper compartment 42 into an upper andlower parts. For moving the injection nozzle 38 between its retractedposition and its extended position, pressurized air is injected in theupper part of the first upper compartment 42 increasing the pressure inthe upper part and moving the piston, and the injection nozzle 38,downward thereby reducing the volume of the lower part. Conversely, inorder to move the injection nozzle 38 between its extended position andits retracted position, pressurized air is injected into the lower partof the first upper compartment 42 increasing pressure in the lower partand moving the piston, and the injection nozzle 38, upward. To regulatethese movements, the respective decreases in pressure/volume in thelower and upper parts of the first upper compartment 42 is controlledand not just openly vented to atmosphere.

A hollow control rod 46 also extends in the chamber 34 along axis A. Thecontrol rod 46 is provided at its lower end with a sealing ring or head48 located in the chamber 32. The sealing ring 48 has a shapecomplementary to the shape of part of the conical portion of theinjection nozzle 38 forming a sealing seat, such that, when the sealingring 48 is applied against the sealing seat, the sealing ring 48 andsealing seat hermetically close the chamber 32 and prevent liquid 35fromflowing through the outlet 30.

The control rod 46 is movable in translation along axis A between aninjecting position, shown in FIG. 3, wherein the sealing ring 48 isspaced from the sealing seat placing the outlet 30 in fluidiccommunication with the inlet 28 via the chamber 32, and a sealingposition, shown in FIGS. 2 and 4, wherein the sealing ring 48 is appliedagainst the sealing seat of the cone portion of the injection nozzle 34.

The housing 40 further includes a second upper compartment 50 arrangedto receive an actuation device 45 for moving the control rod 46. Theactuation device 45 is preferably pneumatic actuation device, similar tothat discussed above in connection with the first upper compartment 42,and is, for example, a piston attached to the control rod 46. Theactuation device 45 thus operates in the same manner as described aboveand, therefore, is not further described herein.

According to the embodiment shown in the FIGS. 2-4, a stretch rod 52extends through the hollow control rod 46, passes through the outlet 30and extends into the preform 2. The stretch rod 52 assists in the axialdeformation of the preform 2. The stretch rod 52 is movable intranslation along axis A in the hollow control rod 46 and is actuated byan appropriate actuation device 54, such as for example a servo motor ora magnetic actuation means. The functioning of the stretch rod 52 isknown and will not be described in detail herein.

For forming and filling a container 1 from a preform 2, once a preform 2has been placed in a mold 22 and the mold closed, the injection nozzle38 is moved in its extended position and the control rod 46 is moved toits injecting position. The liquid 35 from the liquid source 34 thenflows through the outlet 30 and into the inner volume of the preform 2at a predetermined pressure, which may be around 5 bars. At thispressure, the liquid 35 causes the preform 2, which is in a malleablestate, to expand towards the various walls of the molding cavity 26, asseen in FIG. 3. As known, this expansion can be assisted in the axialdirection by extending of the stretch rod 52. In order to completelyurge the wall of the preform against the wall of the molding cavity 26,a pressure peak is applied to the liquid 35 inside the now formedcontainer 2 such that the pressure inside the preform increases up to,for example, around 35 bar, is held for about 0.010 seconds and is thenreduced to about 15 bar. Such a held pressure peak allows for theimprint of designs, letters and logos, on the external surface of thecontainer wall, and in accordance with the present invention, theimprinting of tactile writing, such as braille (a system of touchreading used by blind persons). Forming braille dots, in accordance withbraille standards, has not been heretofore possible in plasticcontainers.

In braille, raised dots are evenly spaced in quadrangularcharacter/letter spaces that are also a fixed width apart. Eachcharacter space is called a cell and may contain up to a maximum of sixdots in a two dots wide and three dots high array. Through the variousarrangements of dots in a cell, 63 different characters can be formed.Provided in a manner that allows the dots to be distinguishable from thebackground, the characters are perceptible by touch with a fingertip.

In accordance with the present invention, a container 1 is providedhaving braille dots 58 in accordance with braille standards. The brailledots 58 are provided on and formed by the surface of the container 1,not a label attached to the container. In a preferred embodiment, thebraille dots 58 meet the standards put forth by the American NationalStandard Institute (ANSI), International Building Code, ANSI 703.4.Accordingly, the braille dots 58 provided on and formed by the surfaceof the container meet the requirements of Table 1.

TABLE 1 MINIMUM TO MAXIMUM MEASURMENT RANGE DIMENSION Dot height 0.025to 0.037 inches (0.6 to 0.9 mm) Dot base diameter 0.059 to 0.063 inches(1.5 to 1.6 mm) Distance between dots in the 0.090 to 0.100 inches samecell (2.3 to 2.5 mm) Distance between corresponding dots 0.241 to 0.300inches in adjacent cells (6.1 to 7.6 mm) Distance between correspondingdots 0.395 to 0.400 inches in cells directly above or below (10.0 to10.2 mm)

More preferably, the braille dots 58 meet the standards put forth by theNational Library Service for the Blind and Physically Handicapped (NLS),Library of Congress, in Specification 800, “Braille Books andPamphlets”, Section 3.2. Accordingly, the braille dots 58 provided onand formed by the surface of the container meet the requirements ofTable 2.

TABLE 2 NOMINAL MEASURMENT RANGE NOMINAL DIMENSION Dot height 0.019inches (0.48 mm) Dot base diameter 0.057 inches (1.44 mm) Distancebetween dots in the same cell 0.092 inches (2.34 mm) Distance betweencorresponding dots 0.245 inches (6.2 mm)  in adjacent cells Distancebetween corresponding dots 0.400 inches (10.0 mm) in cells directlyabove or below

As seen delineated in FIGS. 5 and 6, the containers 1 are generallyformed having the previously mentioned finish 14 from which extends thebody 60 of the container 1. The body 60 may be further delineated asincluding, proceeding away from the finish 14, a shoulder 62, a sidewall64 and a base 66. Between these portions, the body 60 may includevarious transitions, such as recesses, ribs or tapered lands. Each ofthese portions may also have shapes or features other than those seen inthe figures. For example, the shoulder 62 is illustrated as beingconvexly domed, but may be concavely domed, conical, or a combination ofshapes. The sidewall, shown as being a smooth, round cylinder, may beotherwise shaped and/or may include vacuum panels, ribs and otherfeatures. The base 66 may include a smooth, round cylindrical heel 68with a flat profile, as shown, or exhibit a curved profile.

In locating the braille dots 58 with respect to the container 1, asshown in FIGS. 5 and 6 the braille dots 58 are provided on a lowerportion of the shoulder 62 and on the heel 68 of the container 1. Inthis manner, the braille dots 58 are provided in a location that doesnot interfere with or is not interfered by a label attached to thecontainer 1 about the cylindrical sidewall of the container 1. Providingthe braille dots 58 in these locations also allows the container to beheld in one hand while permitting the braille dots 58 to be read by afinger of the other hand of the user. As illustrated, twelve braillecells are provided on each container, six on the shoulder 62 and six onthe heel 68. Depending on the desired text, fewer or greater cells couldbe provided. Individual cells are outlined in phantom, andrepresentatively designated at 70, in FIG. 6.

The braille dots 58 are intended to provide information to the endconsumer, who may be blind or otherwise visually impaired. Theinformation provided may identify the contents of the container, such as“water” or “soap,” may identify a characteristic of the contents, such“danger,” “flammable” or “caustic,” or may provide other information tothe consumer, such as the quantity, e.g. “128 oz.” or a desired feature,e.g. “organic.” The information to be provided is only limited by thenumber of cells 70 that can be provided on the container 1.

As seen in FIG. 7, in forming the braille dots 58, the mold 22 isprovided with recesses 72, in the cavity surface 82, that form part of atactile writing impression 84. The tactile writing impression 84 iscomprised of a plurality of equidistantly spaced cells, and each celldefines a corresponding character formed by six or less of the recesses.Preferably, the size and shape of the recesses 72 in the cavity surface85 of the mold 22 are the same size as specified above for the brailledots 58, and more preferably larger than the size of the desired brailledots 58 to be formed on the container 1. When the recesses 72 are largerthan the braille dots 58, preferably the recesses 72 have a nominal basediameter (d) and depth (h) (from the immediately surrounding cavitysurface 86) that are not more than 10% greater than that the nominalbase diameter (d) and height (h) of the desired braille dots 58, morepreferably not more than 5% greater, and even more preferably betweenabout 2-4% greater.

Optionally, formation of the braille dots 58 may be vacuum assisted.More specifically, the recesses 72 may be directly coupled to a vacuumsource 74 via a vacuum line 76, which is at least partially provided inthe mold 22. As used herein, directly coupled means that the vacuum line76, where provided in the mold 22, terminates in the recess 72 itselfand not otherwise in a surface of the mold 20 defining the mold cavity26.

Once the container 1 is formed and filled with the liquid 35 at the endof the forming step, the control rod 46 moves back to its closedposition, as shown in FIG. 4, and the injection nozzle 38 is moved backto its retracted position. The mold 22 is then opened and the formed andfilled container 1 is retrieved from the mold 22 at an outlet 78 of theforming wheel 20, for example by a second transfer mechanism of a secondtransfer wheel 80, as shown in FIG. 1. The forming station 4 is thenmoved to the inlet 27 of the forming wheel 20, completing one moldingcycle, and receives a new preform 2 and produce another container 1.

As mentioned previously, successive containers 1 can be producedcontinuously and simultaneously by providing several forming and fillingstations 4 distributed on the periphery of the forming wheel 20. As seenin FIG. 1, for illustrative purposes, only eight forming and fillingstations 4 are shown. The number of forming and filling stations 4provided on the forming wheel 20 may be significantly greater than eightand is only limited by the size of the forming wheel 20 and the size ofthe forming and filling stations 4.

Comparative Samples

Optical profilometry (OP) images at six different locations on twoembossed bottles were analyzed to characterize roughness of the featuresdefined at each of the locations. Generally, enhanced roughnessindicates a feature that is defined in greater detail. The two sampleswere created utilizing the same 58.2 gram preforms and mold to produce acontainer from polyethylene terephthalate (PET) having a 40 ouncetargeted fill capacity (excluding overflow capacity) and a 58.2 gramtargeted container weight. In producing the containers, one sample wasformed utilizing pressurized air as the blowing medium and the othersample formed utilizing an incompressible fluid, namely water, as themolding medium. The pressurized air molding process was conducted on aproduction machine and employed conventional parameters currently in usein production runs for the manufacturing of similarly sized and shapedcontainers from PET preforms. The peak air blow pressure of the processwas 40 bar. The molding process using water as the incompressiblemolding medium was conducted on a lab machine and employed parameterssimulating those as might be used in an actual production run for themanufacturing of the containers from PET preforms. The peak liquidmolding (blow) pressure was 35 bar. As a result, the principledifference between the resultant samples was that one utilizedpressurized air as the molding medium (with a peak pressure at 40 bar)and the other used water (with a peak pressure at 35 bar). The resultantsamples were identified as being either “Air Blown” or “Liquid Blown.”

As noted above, the mold 22 used in forming the samples was providedwith various engravings to simulate a wide variety of differentembossments on a resultant container 1. The six locations where the OPimages were take are identified in FIG. 8 at boxes 1-6. Locations 1-3were provided in the sidewall 64 of the container 1, while locations 4-6were provided in the shoulder 62. Location 1 was provided with a surfacetexture pattern, etched pattern no. 800-003 (Custom Etch, Inc., NewCastle, Pa.) and included 0.33 mm/0.013″ recesses in the mold to producea raised pattern on the container. Location 2 was provided with asurface texture pattern, etched pattern no. 800-013 (Custom Etch, Inc.)and included 0.06 mm/0.0025″ recesses in the mold to produce a raisedpattern on the container. Location 3 also included a surface texturepattern, etched pattern no. 800-014 (Custom Etch, Inc.) and included0.09 mm/0.0035″ recesses in the mold to produce a raised pattern on thecontainer. Locations 4-6 included 0.75 mm/0.03″ hemispherical recessesin the mold to produce, respectively, raised double, triple and tripledot patterns on the container.

The OP images were collected using a Contour GT-X8 optical profilometer(Bruker Corporation, Tucson, Ariz.). Image processing proceduresinvolving tilt removal, cylinder removal, a low pass statistic filter,and data restoration were employed. In analyzing the locations 1-3, a4.0 mm×4.0 mm area was imaged by autostitching together multiple 0.6mm×0.4 mm images. In analyzing location 4 a 2.0 mm×4.3 mm area wasimaged and in analyzing locations 5 and 6 a 4.3 mm×4.3 mm area wasimaged, both also by autostitching together multiple 0.6 mm×0.4 mmimages. Top (2-D) views of these areas are shown in the “A” designationsof FIGS. 9-20 and perspective (3-D) views of these areas are shown inthe “B” designations of FIGS. 9-20. The topography differences of theseimages are presented in FIGS. 9-20 (A&B), where purple or deep bluedesignates lowest height areas near the surface of the side wall and reddesignates the highest regions relative to the side wall of thecontainer 1.

Roughness analyses were performed and are expressed as: (1)Root-Mean-Square Roughness, S_(q); (2) Roughness Average, S_(a); (3)Maximum Peak Height, S_(p); (4) Maximum Valley Depth, S_(v); (5) MaximumHeight, S_(z); (6) Roughness Skewness, S_(sk); and (7) RoughnessKurtosis, S_(ku). These roughness analysis parameters are defined asfollows:

Mean (Z_(avg)): The average of all of the Z values in the imaged area;

Root-Mean-Square Roughness (S_(q)): the standard deviation of the Zvalues in the image. It is calculated according to the formula:S_(q)=√{Σ(Z_(i)−Z_(avg))²/N} where Z_(avg) is the average Z value withinthe image; Z_(i) is the current value of Z; and N is the number ofpoints in the image;

Roughness Average (S_(a)): the mean value of the surface relative to thecenter plane and is calculated using the formula: S_(a)=(1/N)Σ|Z_(i)|;

Maximum Peak Height (S_(p)): the tallest height in the profile, relativeto the mean plane;

Maximum Valley Depth (S_(v)): the lowest height in the profile, relativeto the mean plane;

Maximum Height of the Profile (S_(v)): the difference in height betweenthe highest and lowest points of the surface, relative to the meanplane. S_(z)=S_(p)−S_(v);

Roughness Skewness (S_(sk)): a measure of the asymmetry of theprobability distribution of the Z values. S_(sk)=[1/(NS_(q) ³)]Σ(Z_(i)³);

Roughness Kurtosis (S_(ku)): a measure of the peakedness of theprobability distribution of the Z values. S_(ku)=[1/(NS_(q) ⁴)]Σ(Z_(i)⁴);

Fastest Decay Autocorrelation Function (S_(al)): This optional spatialparameter is defined as the length of the fastest decay of the 20% ofthe autocorrelation function, in any direction. A high value for S_(al)indicates the surface is dominated by low frequency components;

Texture Direction of Surface (S_(td)): This optional spatial parameteris the angle of the dominant lay of the surface, relative to the Y axis.This parameter is determined from the Angular Power Spectral DensityFunction; and

Texture Aspect Ratio (S_(tr)): This optional spatial parameter isdefined as the ratio of the fastest decay to the slowest decay tocorrelation 20% of the autocorrelation function. S_(tr) will be closerto 0 for surfaces with a strong lay; S_(tr) will be closer to 1 forsurfaces having a uniform texture.

Regarding the roughness analysis, it is noted that the data was acquiredusing a 20× objective. When analyzed with a 5× objective, The roughsurfaces resulted in significant missing data when analyzed with the 5×objective because that objective has a more limited angular acceptance.A 20× objective provided better data quality, but required stitchingtogether about 100 images instead of 6 images and analysis times wereconsiderably longer than initially expected.

The estimated uncertainties of the roughness values provided are within±3% (at an approximate level of confidence of 95% using a coveragefactor of k=2). Roughness data below 6nm should be viewed as“semi-quantitative” unless a separate z-height calibration in this rangeis performed. “Semi-quantitative” data still allows for comparisonsbetween samples as the precision of the measurement is about ±10%. (Theuncertainty of the absolute roughness values however is not determined.)It is also noted that the uncertainty estimates provided assume thatthere is no variability in roughness between different locationssampled.

The Contour GT-X8 acquires 3-dimensional height information from asurface and stores the data in a digital format. The instrument softwarecan use this height information to perform a variety of statisticalanalyses from the entire imaged area (.e.g. S_(q), S_(a), S_(p), S_(v),and S_(z)). Additional roughness statistics, spatial statistics, andvolume statistics could be calculated for the whole or for a selectedportion of the image.

The results of the roughness analyses are presented below in Table 3. Asnoted above, the images of the analyzed locations from the Air Blownbottle are provided in FIGS. 9, 11, 13, 15, 17,and 19, while the imagesof the analyzed locations from the Liquid Blown bottle are provided inFIGS. 10, 12, 14, 16, 18 and 20. As summarized and shown in Table 3 bythe consistently higher values, the analyzed locations on the LiquidBlown bottle were consistently rougher than the analogous locations onthe Air Blown bottle, and therefore better formed surface texture.

TABLE 3 Roughness Results—Height Parameters Sample ID Location S_(a)(μm) S_(q) (μm) S_(p) (μm) S_(v) (μm) S_(z) (μm) S_(sk) S_(ku) Air Blown1 12.14 14.11 36.04 −52.87 88.91 0.48 2.54 2 4.52 5.93 17.45 −39.4856.93 −0.68 4.62 3 6.96 8.91 27.39 −41.66 69.05 −0.11 3.55 4 20.72 24.8062.11 −24.36 86.47 0.99 2.50 5 15.23 21.20 68.18 −28.90 97.08 1.59 4.276 17.01 21.69 74.64 −33.18 107.82 1.51 4.03 Liquid 1 26.00 28.01 47.73−75.18 122.91 0.00 1.49 Blown 2 10.96 12.91 32.46 −48.20 80.66 −0.302.37 3 11.65 13.78 62.48 −54.97 117.45 −0.49 2.60 4 85.89 99.58 210.66−98.03 308.69 0.70 1.85 5 62.47 84.10 222.02 −124.99 347.01 1.16 3.07 668.02 80.78 207.58 −120.85 328.43 1.11 2.77

TABLE 4 Section Analysis Results Diameter Height (X-Profile) (Y-Profile)Sample ID Location (mm) (μm) AirBlow 4 1.70 81.05 5 1.72 78.84 6 1.6980.30 Liquid Form 4 1.67 273.70 5 1.69 266.36 6 1.67 258.95

Section analyses were performed to measure the dimensions of the brailledots/characters in locations 4-6. The profiles were created by measuringthe height values across lateral regions (x and y positions shown in the2-D images) of FIGS. 21-26 (“A” designations). The heights of thesefeatures were determined from the profiles by measuring the differencesin z-height between the two cursors. Similarly, the lateral dimensionswere determined by measuring the differences x- or y-position. The greenand red cursors indicate the measurement and reference locations,respectively. The widths (“ΔX”) and heights (“ΔZ”) are listed above thegraphs. The heights and diameters of the braille dots, as measured bythe above section analysis, are summarized in Table 4. As seen therein,the Liquid Blown container had much taller dots, which is consistentwith the Liquid Blown container having higher S_(z) values, as seen inTable 3.

As noted above, in locations 4, 5 and 6, the braille dots were formed byproviding 0.75 mm hemispherical depressions in the mold at the relativelocations. The average height utilizing the air blow process for thebraille dots was therefore 80.06 μm. For the braille dots formed by theliquid blow process, the average height was 266.34 μm. As seen fromthese averages, even while utilizing a lower peak pressure, 35 barversus 40 bar, the resulting liquid blown container provided brailledots that were, on average, 3.3 times greater in height than the airblown container.

Relative to the depression provided in the mold for forming the brailledots, the ratio of the depth of the depression to the height of theresulting braille dot was over 9:1 for the for the air blown containerand less than 3:1 for the liquid blown container. Extrapolating theseresults, the depression in the mold would have to be at least 3 times asdeep in order to form a braille dot feature of similarly height usingair as the blowing medium. Notably, the resulting width of the featurewould negate its use in the braille tactile writing system.

A relief factor (R_(f)) can also be defined for the resultant brailledot features by the formula R_(f)=H_(r)/H_(m), where H_(r) is the heightof the feature and H_(m) is the depth of the relief in mold used to formthe feature. In the air blown container, the relief factor Rf=0.11; andin the liquid blown container the relief factor Rf=0.35.

As a person skilled in the art will really appreciate, the abovedescription is meant as an illustration of at least one implementationof the principles of the present invention. This description is notintended to limit the scope or application of this invention since theinvention is susceptible to modification, variation and change withoutdeparting from the spirit of this invention, as defined in the followingclaims.

1. A method of forming a container of plastic material, the methodcomprising the steps of: providing a preform of the plastic material,the preform including an open end defined by a mouth, a closed end and agenerally cylindrical body extending between the closed end and themouth; placing the preform within a mold having surfaces defining acavity corresponding in shape to the container; injecting anincompressible medium under pressure into the preform, theincompressible medium being an end product remaining in the moldedcontainer; expanding the preform in the cavity under the influence ofthe incompressible medium into contact with the surfaces defining thecavity and simultaneously forming and filling the container; duringexpanding of the preform, forcing portions of the plastic material intoa series of recesses defined in the cavity surface, each of the recesseshaving a common depth; removing the container with the incompressiblemedium contained therein from the mold, the container including a seriesof raised dots corresponding to the series of recesses defined in thecavity surface.
 2. The method according to claim 1, wherein the recessesare provided in a portion of the cavity defining one of a shoulder orbase of the container.
 3. The method according to any of the precedingclaims, wherein the recesses are provided adjacent to a portion defininga sidewall of the container.
 4. The method according to any of thepreceding claims, wherein the recesses and the raised dots define adepth to height ratio of less than 9:1.
 5. The method according to anyof the preceding claims, wherein the recesses and the raised dots definea depth to height ratio of less than 3:1.
 6. The method according to anyof the preceding claims, wherein the recesses and the raised dots definea relief factor of greater than 0.11.
 7. The method according to any ofthe preceding claims, wherein the recesses and the raised dots define arelief factor of greater than 0.3.
 8. The method according to any of thepreceding claims, wherein the incompressible medium is injected at apressure of less than 40 bar.
 9. The method according to any of thepreceding claims, wherein the incompressible medium is injected at apressure of less than 36 bar.
 10. The method according to any of thepreceding claims, wherein the incompressible medium is injected at apressure in the range of 30 to 35 bar.
 11. The method according to anyof the preceding claims, wherein the incompressible medium is injectedwith a peak pressure of less than 40 bar.
 12. The method according toany of the preceding claims, wherein the incompressible medium isinjected with a peak pressure of less than 36 bar.
 13. The methodaccording to any of the preceding claims, wherein the incompressiblemedium is injected with a peak pressure in the range of 30 to 35 bar.14. The method according to any of the preceding claims, wherein each ofthe raised dots extends from an immediately surrounding surface of themolded container to a nominal height of not less than 0.2 mm, morepreferably greater than 0.25 mm and most preferably greater than 0.258mm.
 15. The method according to any of the preceding claims, wherein theseries of raised dots define a tactile writing feature.
 16. The methodaccording to any of the preceding claims, wherein the series of raiseddots define a tactile writing feature comprised of a plurality ofequidistantly spaced cells and each cell including a character formed bynot more than six of the raised dots.
 17. The method according to any ofthe preceding claims, wherein each of the raised dots has a nominal basediameter in the range of greater than 1.4 mm to less than 1.7 mm
 18. Amolded container of plastic material, the molded container comprising: aneck defining an opening into the molded container; a body extendingfrom the finish and including a shoulder adjacent the finish, a basedefining a closed end of the container, and a sidewall extending betweenthe shoulder and the base; and a series of raised dots defining tactilewriting feature formed on a surface of the container and being definedby the plastic material forming the container.
 19. The containeraccording to claim 18, wherein the tactile writing feature is formed onat least one of the shoulder and the base.
 20. The container accordingto claim 18, wherein the tactile writing feature is formed adjacent tothe sidewall on at least one of the shoulder and the base.
 21. Thecontainer according to any of claims 18-20, wherein each of the raiseddots extends from an immediately surrounding surface of the moldedcontainer to a nominal height of not less than 0.2 mm, more preferablygreater than 0.25 mm and most preferably greater than 0.258 mm.
 22. Thecontainer according to any of claims 18-21, wherein each of the raiseddots extends from an immediately surrounding surface of the moldedcontainer to a nominal height of between 0.25 mm and 0.6 mm.
 23. Thecontainer according to any of claims 18-22, wherein each of the raiseddots has a nominal base diameter of not more than 1.69 mm.
 24. Thecontainer according to any of claims 18-23, wherein each of the raiseddots has a nominal base diameter in the range of 1.4 mm to less than 1.7mm and extends from an immediately surrounding surface of the moldedcontainer to a nominal height in the range of 0.25 mm to less than 0.9mm.
 25. The container according to any of claims 18-24, wherein thetactile writing feature is comprised of a plurality of equidistantlyspaced cells and each cell including a character formed by not more thansix of the raised dots.
 26. A method of forming a molded container ofplastic material, the method comprising the steps of: providing apreform of the plastic material; placing the preform within a moldhaving cavity surfaces defining a cavity corresponding in shape to adesired shape of the container; injecting an incompressible medium underpressure into the preform, the incompressible medium being an endproduct remaining in the molded container; expanding the preform in thecavity under the influence of the incompressible medium into contactwith the cavity surfaces and simultaneously forming and filling themolded container with a shape extending from a neck defining an openinginto the molded to a base defining a closed end of the molded container;during expanding of the preform, forcing portions of the plasticmaterial into recesses in the cavity surfaces that form part of aembossed texture on a surface of the container; and removing thecontainer from the mold wherein the resulting embossed texture on thecontainer has a roughness average S_(a) that is at least 40% greaterthan the roughness average S_(a) of the corresponding embossed textureof a container molded in the same mold using pressurized air.
 27. Amolded container of plastic material, the container comprising: a neckdefining an opening into the molded container, a body extending from theneck and including a base defining a closed end of the molded container;embossed texture being formed on a surface of the plastic container andbeing defined by the plastic material forming the molded container,wherein the embossed texture has a roughness average S_(a) that is atleast 40% greater than the roughness average S_(a) of the correspondingembossed texture of a container molded in the same mold usingpressurized air.